JPH04277518A - Thermosetting resin composition and its cured product - Google Patents

Abstract

PURPOSE:To obtain the title composition which can give a cured product having high mechanical strengths and glass transition temperature and excellent moldability, moisture resistance, head resistance and adhesion by using a specified epoxy resin and/or phenolic resin. CONSTITUTION:The title composition comprises a naphthalenic epoxy resin of formula I [wherein R<0> is H or glycidyl; R<2> is H or 1-6C (substituted) hydrocarbyl; and R<1> is R<2> or halogen] and/or a naphthalenic phenolic resin (e.g. a compound of formula II).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a cured product that has low melt viscosity, excellent molding properties, high mechanical strength, and high glass transition temperature, as well as low hygroscopicity, low linear expansion, and high adhesiveness. The present invention relates to a thermosetting resin composition suitable for use particularly in thin semiconductor packages.

0002

[Prior art and problems to be solved by the invention] Conventionally,
A thermosetting resin composition containing an epoxy resin, a phenol resin as a hardening agent for the epoxy resin, and an inorganic filler is used for semiconductor packages.

However, as semiconductor packages have become thinner in recent years, various problems have arisen. For example, when a flat package is mounted on a printed circuit board, the package is immersed in a high-temperature solder bath. At this time, packages made of conventional thermosetting resin compositions may crack due to thermal shock, or It has been pointed out that if a flat package absorbs moisture before it is mounted on a board, a water vapor explosion will occur in the package when it is immersed in a high-temperature solder bath, causing cracks. Therefore, as a countermeasure to this problem, improvements are being considered from both the frame and the resin.As for the resin, in addition to performance such as high mechanical strength and high glass transition temperature, it also has low hygroscopicity and wire resistance. Performance requirements include a small coefficient of expansion and good adhesion to the frame. The present inventors have already published Japanese Patent Application No. 1559/1999 as an epoxy resin composition having such performance.
No. 6, No. 2-160489, and No. 2-292715 show that epoxy resins containing naphthalene rings and phenol resins as main components have excellent characteristics that have not been seen before as resins for thin packages. Proposed. Furthermore, JP-A-62-143920, JP-A-2-23591
A similar proposal is also described in Publication No. 8. However, these naphthalene ring-containing epoxy resins and phenolic resins have a high softening point due to their high degree of polymerization, and when producing epoxy resin compositions using these types of resins, the amount of inorganic filler filled must be There may be limitations, and
When molding a package with a large number of pins, there is a risk that the island may be deformed due to the high melt viscosity of the resin.

Furthermore, epoxy resins made by converting 1,6-dihydroxynaphthalene into glycidyl ether are also commercially available, and since this epoxy resin has a very low melt viscosity, it is possible to incorporate a large amount of filler into the resin composition. Therefore, the expansion coefficient can be significantly reduced. However, a semiconductor device encapsulated with a resin composition containing this epoxy resin as a main component has a drawback that its moisture resistance is poor, and its cured product loses a large amount of weight at high temperatures, particularly at temperatures of 200° C. or higher.

[0005]

[Means and effects for solving the problems] In view of the above circumstances, the present inventors have made extensive studies to obtain a thermosetting resin composition with higher performance, and have found that the naphthalene ring represented by the following formula (I) Since the epoxy resins and phenolic resins contained therein have a large hydrophobic naphthalene ring with high rigidity, they have good reactivity and low melt viscosity, and these naphthalene resins are used as phenolic resins that act as epoxy resins and their curing agents. By blending a ring-containing epoxy resin and/or a phenolic resin, the amount of inorganic filler can be greatly increased. It was discovered that a thermosetting resin composition suitable for use in semiconductor packages can be obtained, giving a cured product having mechanical strength, high glass transition temperature, low hygroscopicity, low coefficient of linear expansion, and high adhesiveness, and the present invention This is what we have come to do.

[0006]

[Formula 2] (However, in the formula, R0 is a hydrogen atom or a glycidyl group, R1 is a hydrogen atom, a halogen atom, or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, and R2 is a hydrogen atom or a carbon number 1 ~
6 unsubstituted or substituted monovalent hydrocarbon groups. )

00
[07] To explain the present invention in more detail below, the thermosetting resin composition according to the present invention comprises a naphthalene ring-containing epoxy represented by the structural formula (I) below as an epoxy resin and a phenol resin as a curing agent for the epoxy resin. resin and/or
Alternatively, a phenol resin may be added. These naphthalene ring-containing epoxy resins and phenolic resins have a highly rigid and highly hydrophobic naphthalene ring, so unlike conventional naphthalene ring-containing resins,
It is a material with good reactivity and low melt viscosity.

[0008]

[Chemical formula 3]

Here, R0 in formula (I) is a hydrogen atom or a glycidyl group. Further, R1 is a hydrogen atom, a halogen atom, or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, and specifically, a hydrogen atom, a chlorine atom, a bromine atom,
Lower alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, or some or all of the hydrogen atoms of these groups are fluorine,
Examples include a chloromethyl group, a bromoethyl group, and a 3,3,3-trifluoropropyl group substituted with a halogen atom such as chlorine or bromine. Further, R2 is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, such as a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t Examples include lower alkyl groups such as -butyl groups, aryl groups such as phenyl groups, and groups in which some or all of the hydrogen atoms of these groups are substituted with the same halogen atoms as mentioned above.

Specific examples of such epoxy resins and phenol resins of formula (I) include the following compounds.

[0011]

[C4]

[0012] When the epoxy resin and phenol resin of the above formula (I) are used for semiconductor encapsulation, the hydrolyzable chlorine content is 1000 ppm or less, preferably 500 ppm.
Hereinafter, it is preferable that sodium and potassium are 10 ppm or less. Hydrolyzable chlorine is 1000 ppm or more,
When a semiconductor device is sealed with a resin containing 10 ppm or more of sodium or potassium and left in a high temperature and high humidity environment for a long time, the moisture resistance tends to deteriorate.

The above-mentioned naphthalene ring-containing phenolic resin of formula (I) is prepared by condensing 1,6-dihydroxynaphthalene with a compound having a phenolic hydroxyl group such as phenol or cresol, or with formalin or salicylaldehyde in a conventional manner. It can be easily synthesized by In this case, the blending ratio of 1,6-dihydroxynaphthalene and phenols, etc. is 1:0.8 to 1:1.2.
If the blending ratio deviates from the above ratio, the desired naphthalene ring-containing phenolic resin will not be obtained, and the composition ratio of 1,6-dihydroxynaphthalene and phenols in the product will not match the blending ratio of the raw materials. Different resins and polymers may be obtained. Furthermore, the naphthalene ring-containing epoxy resin of formula (I) can be obtained by reacting the naphthalene ring-containing phenol resin of formula (I) obtained as described above with epichlorohydrin under the same operation and reaction conditions as conventional epoxy resins. Can be easily synthesized.

In the present invention, in order to reduce the viscosity of the resin, (I)
It is preferable that the epoxy resin and phenol resin of the formula account for 50% by weight or more of the total epoxy resin and phenol resin in the composition. If it is less than 50% by weight, the melt viscosity of the resin will increase and the amount of inorganic filler filled will increase. It may not be possible to raise the temperature, or it may cause trouble during molding.

In the present invention, in addition to the epoxy resin and phenol resin of formula (I), other conventionally used epoxy resins and phenol resins can also be used in combination.

In this case, the other epoxy resin may be any resin as long as it has at least two epoxy groups in one molecule; for example, bisphenol A
Examples include epoxy resins such as type epoxy resins, novolac type epoxy resins, alicyclic epoxy resins, glycidyl type epoxy resins, and epoxy resins represented by the following formulas. Further, these epoxy resins may be combined as appropriate.

[0017]

[C5]

These epoxy resins have a softening point of 50°C to 1
It is desirable to have an epoxy equivalent of 100 to 400 at 00°C.

Other phenolic resins act as curing agents for epoxy resins in the same way as the naphthalene ring-containing phenolic resin of formula (I), such as phenolic novolak resins, cresol novolak resins, triphenolmethane, etc. Those having two or more hydroxyl groups and those having the structure shown below can be used.

[0020]

[C6]

Further, among the above-mentioned phenolic resins, those having a softening point of 60°C to 120°C are preferable, and those having a hydroxyl equivalent of 90 to 150 are preferable.

[0022] For flame retardancy, bromine-containing epoxy resins such as brominated epoxy resins, phenolic resins, etc. can also be used.

In the present invention, phenolic resin ((I)
The amount of the naphthalene ring-containing phenolic resin and other phenolic resins (formula (I)) to be used is such that the equivalent ratio of epoxy groups to hydroxyl groups in the epoxy resin (naphthalene ring-containing epoxy resin and other epoxy resins of formula (I)) is from 0.5 to 0.5. Any amount may be used as long as it is within the range of 2, but usually the epoxy resin is 10
It is preferably 30 to 100 parts by weight, particularly 40 to 70 parts by weight relative to 0 parts by weight. If it is less than 30 parts by weight, sufficient strength may not be obtained; on the other hand, if it exceeds 100 parts by weight, unreacted phenol resin may remain, reducing moisture resistance.

It is preferable to add a stress reducing agent to the thermosetting resin composition of the present invention in order to impart flexibility to the cured product. As the stress reducing agent, for example, the following (II
), thermoplastic resins such as methyl methacrylate-styrene-butadiene copolymer, styrene-ethylene-butene-styrene copolymer, and fine powders such as silicone gel and silicone rubber can be added. can.

[0025]

embedded image (However, R0 is the same as in formula (I), and n is an integer of 0 or more.)

Furthermore, the surface of the inorganic filler may be treated with a two-component type silicone rubber or silicone gel, but among these, silicone-modified resin of the formula (II) above or styrene-modified resin may be used.
Butadiene-methyl methacrylate copolymer is effective in reducing stress in epoxy resins.

The amount of these stress reducing agents used is usually 0.5 to 10% by weight, particularly preferably 1 to 5% by weight, based on the entire thermosetting resin composition. If the amount is less than 0.5% by weight, sufficient thermal shock resistance may not be provided, while if it exceeds 10% by weight, mechanical strength may decrease.

In the present invention, an inorganic filler can be further added. The inorganic filler is used to reduce the expansion coefficient of the sealing material and reduce the stress applied to the semiconductor element. As specific examples, crushed or spherical fused silica and crystalline silica are mainly used, but alumina, silicon nitride, aluminum nitride, etc. can also be used. In order to achieve both low expansion and moldability of the cured product, it is better to use a blend of spherical and crushed products, or only spherical products. Note that the average particle size of the inorganic filler is preferably 5 to 20 microns. Moreover, it is better to use this type of inorganic filler after surface treatment with a silane coupling agent in advance.

The amount of inorganic filler to be filled is 200 to 1 part by weight per 100 parts by weight of the total amount of epoxy resin and phenol resin.
600 parts by weight is preferable; if it is less than 200 parts by weight, the expansion coefficient will increase, stress applied to the semiconductor element will increase, and device characteristics may deteriorate; if it exceeds 1,600 parts by weight, the viscosity during molding will increase. , moldability may deteriorate.

It is preferable to add a curing catalyst to the composition of the present invention, typical examples of which include imidazole or its derivatives, phosphine derivatives, and cycloamidine derivatives. The amount of catalyst is preferably 0.001 to 5 parts by weight, particularly 0.1 to 2 parts by weight, based on 100 parts by weight of the epoxy resin, and if it is less than 0.001 parts by weight, curing may not be possible in a short time. If the amount exceeds 5 parts by weight, the curing speed may be too fast and a good molded product may not be obtained.

In addition to the above-mentioned components, the thermosetting resin composition of the present invention may optionally contain other optional components such as a mold release agent such as carnauba wax, higher fatty acids, and synthetic waxes.
Furthermore, a silane coupling agent, antimony oxide, a phosphorus compound, etc. may be added.

The composition of the present invention can be produced by melt-kneading the above-mentioned components using heated rolls, a kneader, a continuous extruder, or the like. Note that there is no particular restriction on the order of blending the components.

The epoxy resin composition of the present invention thus obtained can be used in DIP type, flat pack type, PLCC type, etc.
It is effective for semiconductor packages such as type, SO type, etc. In this case,
This can be carried out by employing conventional molding methods such as transfer molding, injection molding, and casting. The molding temperature of the epoxy resin composition of the present invention is 150 to 180°C, and the post-cure temperature is 150°C.
Preferably, the reaction is carried out at ˜185° C. for 2 to 16 hours.

[0034]

[Effects of the Invention] The thermosetting resin composition of the present invention has (I)
By blending the naphthalene ring-containing epoxy resin and/or phenol resin of the formula, it has low melt viscosity and excellent molding properties, as well as high mechanical strength and high glass transition temperature.
Provides a cured product with excellent moisture resistance, heat resistance, and adhesion. Therefore, the composition of the present invention can be particularly suitably used for thin semiconductor packages.

[0035]

[Examples] The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, in the following examples, all parts indicate parts by weight.

[Example, Comparative Example] In addition to the components shown in Table 1, γ-glycidoxypropyltrimethoxysilane 1.5
parts, wax E 1.5 parts, carbon black 1.0 parts,
The mixture obtained by adding 0.8 part of triphenylphosphine was uniformly melt-kneaded using two heated rolls to produce eight types of thermosetting resin compositions (Examples 1 to 5, Comparative Example 1). ~3
).

The following properties (a) to (d) were measured for these epoxy resin compositions. (a) Using a mold that complies with spiral flow EMMI standards at 175°C and 70k.
It was measured under the condition of g/cm2. (b) Mechanical strength (bending strength, bending modulus) JISK6
A bending rod of 10 x 100 x 4 mm was molded under the conditions of 175°C, 70 kg/cm2, and 2 minutes of molding time according to 911.
Measurements were made after post-curing at 180°C for 4 hours. (c) Glass transition temperature, expansion coefficient 175℃, 70kg/cm2, molding time 2 minutes 4
A test piece of 4 x 15 mm was molded, post-cured at 180°C for 4 hours, and measured using a dilatometer by raising the temperature at 5°C per minute. (d) Moisture absorption amount after moisture absorption, solder crack resistance and moisture resistance 17
A semiconductor device for moisture resistance testing for aluminum wiring corrosion measurement was sealed in a flat package with a thickness of 2 mm under the conditions of 5° C., 70 kg/cm 2 and a molding time of 2 minutes, and post-cured at 180° C. for 4 hours. This package is 85℃/85
%RH atmosphere for 72 hours to perform moisture absorption treatment, measure the amount of moisture absorption, and place it in a solder bath at 260°C for 10 hours.
Dipped for seconds. After confirming the number of cracks that occurred in the package at this time, only the non-defective products were left in a saturated steam atmosphere at 120° C. for a predetermined period of time, and the defect occurrence rate was examined. (e) Adhesion A cylindrical molded product with a diameter of 15 mm and a height of 5 mm was molded on a 42 alloy plate under the conditions of 175°C, 70 kg/cm2, and a molding time of 2 minutes, and after post-curing at 180°C for 4 hours, a push-pull gauge was used. The peel force between the molded product and the 42 alloy plate was measured.

[0038]

[Table 1]

[0039]

[Chemical formula 8]

[0040]

[Chemical formula 9] ** BERN-S: Brominated epoxy resin (manufactured by Nippon Kayaku Co., Ltd.)

Claims (1)

[Claims] 1. A thermosetting resin composition comprising a naphthalene ring-containing epoxy resin and/or a phenol resin represented by the following formula (I). [Formula 1] (However, in the formula, R0 is a hydrogen atom or a glycidyl group, R1 is a hydrogen atom, a halogen atom, or an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, and R2 is a hydrogen atom or a carbon number 1 ~
6 unsubstituted or substituted monovalent hydrocarbon groups. ) [Claim 2] A cured product obtained by curing the thermosetting resin composition according to Claim 1.